SAN FRANCISCO — From California, with its counterculture heritage, to the fishing ports and mill towns of Maine, millions of Americans in nine states have a chance to vote Nov. 8 on expanding legal access to marijuana. Collectively, the ballot measures amount to the closest the U.S. has come to a national referendum on the drug.

Five states — Arizona, California, Maine, Massachusetts and Nevada — will consider legalizing the recreational use of pot. Three others — Florida, Arkansas and North Dakota — will decide whether to permit marijuana for medical purposes. Montana will weigh whether to ease restrictions on an existing medical marijuana law.

As the most populous state, with a reputation for trend-setting, California is attracting the most attention — and money — in an intensifying debate over Proposition 64.

Silicon Valley tycoons and deep-pocketed donors with connections to the legal medical marijuana industry are among the top financial backers of a pro-pot campaign that has raised almost $17 million. Opponents have raised slightly more than $2 million, including a $1.4 million contribution from retired Pennsylvania art professor Julie Schauer.

Advocates on both sides say passage in California would likely ignite legalization movements in other states, especially when the tax dollars start adding up. California’s nonpartisan Legislative Analyst’s Office estimated the state could collect up to $1 billion a year in marijuana taxes.

“As California goes, so goes the nation,” said University of California, Berkeley political science professor Alan Ross.

If “yes” votes prevail across the country, about 75 million people accounting for more than 23 percent of the U.S. population would live in states where recreational pot is legal. The jurisdictions where that’s already the case — Alaska, Colorado, Oregon, Washington state and the District of Columbia — have about 18 million residents, or 5.6 percent of the population. Twenty-five states allow medical marijuana.

According to national polls, a solid majority of Americans support legalization. Gallup’s latest survey gauged support at 58 percent, up from 12 percent from when the question was first posed in 1969. Gallup says 13 percent of U.S. adults report using marijuana at present, nearly double the percentage who reported using pot in 2013.

California voters rejected an attempt to legalize recreational marijuana in 2010 after campaign leaders struggled to raise money and support for a four-page ballot measure hastily written by the owner of a small medicinal marijuana store.

This time, the 62-page ballot measure was crafted by political professionals and has the backing of many elected officials, including Lt. Gov. Gavin Newsom, who is running for governor in 2018. Current Gov. Jerry Brown says he’s close to announcing his position.

The measure would allow people 21 and older to legally possess up to an ounce of weed and grow six marijuana plants at home. Pot sales would be subject to various tax rates that would be deposited into the state’s Marijuana Tax Fund. Most of that money would be spent on substance-abuse education and treatment. Some would be used to repair environmental damage caused by illegal growers.

Opponents argue that the measure will do more harm than good by opening a marijuana market dominated by small farmers to corporate interests and encouraging children to use the drug through pot-laced sweets like gummy bears, cookies and brownies.